JP4970013B2 - Oxygen partial pressure controller - Google Patents

Description

  The present invention relates to an oxygen partial pressure control apparatus.

  Conventionally, a method for producing a single crystal sample or the like using an atmospheric gas whose oxygen partial pressure is controlled by an oxygen partial pressure control device having an electrochemical oxygen pump containing a solid electrolyte is known (Patent Document). 1).

  The oxygen partial pressure control apparatus shown in FIG. 11 includes a mass flow controller (MFC) 3 that controls the flow rate of the inert gas that has passed through the valve 2 to a set value, and the inert gas that has passed through the mass flow controller 3 as a target oxygen component. The oxygen oxygen for supply gas supplied to the next process (apparatus) such as a sample growing apparatus by monitoring the oxygen partial pressure of the inert gas controlled by the oxygen pump 4 and the inert gas controlled by the oxygen pump 4 It has a sensor 5.

Further, this apparatus compares the monitored value by the oxygen sensor 5 with the set value by the oxygen partial pressure setting unit 6 and the inertness sent out from the oxygen pump 4 to set a desired oxygen partial pressure value. An oxygen partial pressure control unit 7 that controls the oxygen partial pressure of the gas to a predetermined value and an oxygen partial pressure display unit 8 that displays a monitor value by the oxygen sensor 5 are provided. Normally, the oxygen partial pressure in the inert gas is about 10 ⁻⁴ atm.

As shown in FIG. 12, the electrochemical oxygen pump 4 has electrodes 4b and 4c made of platinum formed on both inner and outer surfaces of a solid electrolyte cylindrical body 4a having oxide ion conductivity. The solid electrolyte cylindrical body 4a is, for example, a zirconia solid electrolyte and is heated by a heater (not shown). An inert gas is supplied in the axial direction from one opening of the solid electrolyte cylindrical body 4a toward the other opening. The inert gas is, for example, Ar + O ₂ (10 ⁻⁴ atm). A DC voltage of a DC power source E is applied between the inner and outer electrodes 4b and 4c. When a positive electrode is applied to the outer electrode 4c and a negative electrode is applied to the inner electrode 4b to flow a current I, oxygen molecules (O ₂ ) in the inert gas flowing through the solid electrolyte cylindrical body 4a are electrically charged. It is reduced to ions (O ²⁻ ) and released again as oxygen molecules (O ₂ ) through the solid electrolyte to the outside of the solid electrolyte cylindrical body 4a. Oxygen molecules released to the outside of the solid electrolyte cylindrical body 4a are exhausted together with an auxiliary gas such as air. The inert gas of Ar + O ₂ (10 ⁻⁴ atm) supplied to the solid electrolyte cylindrical body 4a becomes a processed gas (purified gas) that is controlled to a target oxygen partial pressure by reducing oxygen molecules, and is the next step. (Device).

In addition, the oxygen pump 4 of FIG. 12 can also perform a pump operation by applying a DC voltage having a polarity opposite to that described above between the electrodes 4b and 4c on the inner and outer surfaces of the solid electrolyte cylindrical body 4a. That is, when a negative electrode is applied to the outer electrode 4c and a positive electrode is applied to the inner electrode 4b, oxygen molecules (O ₂ ) in a gas such as air flowing along the outer surface of the solid electrolyte cylindrical body 4a are solid. It is electrically reduced by the electrolyte to be ionized (O ²⁻ ), and is released again as oxygen molecules (O ₂ ) through the solid electrolyte into the solid electrolyte cylindrical body 4a. In this case, the oxygen partial pressure of the inert gas flowing inside the solid electrolyte cylindrical body 4a is increased and fed to the outside.

If a gas whose oxygen partial pressure is controlled by such an oxygen pump is supplied, crystal growth, alloying, heat treatment, semiconductor manufacturing process, etc. can be performed in an atmosphere such as an inert gas whose oxygen partial pressure is controlled.
JP 2002-326887 A

  In the oxygen pump shown in FIG. 12, a single circular pipe-shaped solid electrolyte cylindrical body is used. That is, the gas to be treated is caused to flow in the axial direction in the internal space of the single solid electrolyte cylindrical body, and the ionic conductivity is pumped inside and outside the solid electrolyte partition wall while flowing through the solid electrolyte cylindrical body. The gas flow rate that can be processed by such a gas pump is proportional to the contact area between the gas to be processed and the outer surface of the solid electrolyte cylindrical body. Therefore, in order to increase the gas flow rate, it is necessary to increase the contact area between the gas to be processed and the outer surface of the solid electrolyte cylindrical body.

  To that end, it is conceivable to lengthen the solid electrolyte cylindrical body or increase the pipe diameter. In order to effectively use the oxygen ion conductive solid electrolyte, it is necessary to reduce the resistance value of the oxygen pump as much as possible and increase the oxygen permeation ability of the oxygen pump. The resistance value of the oxygen pump is affected by the shape (surface area and thickness) of the solid electrolyte, the electrode film, the lead terminal, and the like. Among these, the shape of the solid electrolyte has a large surface area, and the resistance value decreases as the thickness decreases. That is, when considering a cylindrical body, a shape having a large diameter and length and a small thickness is preferable. However, in view of the ease of manufacturing the solid electrolyte cylindrical body and the strength of the solid electrolyte cylindrical body used in a heated and high temperature holding state, there are limits to the diameter, length, and thickness. In addition, as the pipe diameter increases, the ion conduction reaction of the gas to be processed flowing through the center of the solid electrolyte cylindrical body decreases rapidly, and as a result, the gas to be processed flowing through the center passes through without reaction. In addition, control accuracy such as oxygen partial pressure decreases. For this reason, there is a limit to simply increasing the pipe diameter of the solid electrolyte cylindrical body. Therefore, there is a limit in increasing the contact area between the gas to be treated and the solid electrolyte cylindrical body by the above method. For this reason, the gas flow rate that can be processed substantially effectively by the gas pump is limited, and the application of supplying gas with controlled oxygen partial pressure is limited.

  In view of the above problems, the present invention can supply purified gas in a clean state to other devices such as a sample preparation chamber without causing shortage of gas (purified gas) whose oxygen partial pressure is controlled, and is compact. An oxygen partial pressure control apparatus capable of achieving the above is provided.

The oxygen partial pressure control apparatus of the present invention comprises a circulation circuit having a gas purification unit for purifying a gas whose oxygen partial pressure is controlled in the range of 0.2 to ^10-30 atm and a tank, and a raw material filled in the tank An oxygen partial pressure control device that circulates gas in the circulation circuit and stores the purified gas purified in the gas purification unit in a tank, wherein the tank is disposed at a lower position in the circulation circuit, and the gas flow The outlet is disposed at an upper position, and the purified gas in the tank is supplied to the other device via the gas outlet.

  According to the oxygen partial pressure control apparatus of the present invention, the source gas filled in the tank can be circulated through this circulation circuit, and the purified gas purified in the gas purification unit can be stored in the tank. For this reason, purified gas can be stably supplied to another apparatus. In addition, when supplying the purified gas to another apparatus, the purified gas in the tank disposed at the lower position is supplied from the gas outlet at the upper position to the other apparatus, so impurities such as contaminants are purified gas. Even if it is mixed in, it stays between the tank and the gas outlet or in the tank to prevent such impurities from flowing out from the gas outlet.

  An oxygen partial pressure setting unit for setting a desired oxygen partial pressure value, and a monitored value by the oxygen sensor is compared with a set value by the oxygen partial pressure setting unit to set the oxygen partial pressure of the inert gas sent from the oxygen pump to a predetermined value. It is preferable that an electric control unit having an oxygen partial pressure control unit to be controlled is provided, and this electric control unit is arranged on one side of the box in which the circulation circuit is accommodated.

  Further, a pump for circulating the gas in the circulation circuit is arranged at an intermediate position in the vertical direction of the box.

  In the present invention, the purified gas purified by the gas purification unit can be stored in the tank, and the purified gas can be stably supplied to other apparatuses. Moreover, since the purified gas is purified by the gas circulating in the circulation circuit, the purified gas in a clean state can be purified, and high-quality purified gas can be supplied to other devices. That is, in the case where the purified gas supplied to other apparatuses is returned and sequentially supplied to the gas purification unit, it is difficult to maintain a clean state and there is a possibility that quality may be deteriorated.

  Furthermore, since the purified gas in the tank disposed at the lower position is supplied from the gas outlet at the upper position to other devices, even if impurities such as contamination are mixed into the purified gas, the tank and the gas outlet It stays between and in the tank to prevent the outflow of such impurities from the gas outlet. For this reason, the purified gas in a stable and clean state can be supplied to another apparatus, and the other apparatus can stably perform high-precision processing using this purified gas.

  The gas purification unit includes an electrochemical oxygen pump that can control the gas to a target oxygen partial pressure, and an oxygen sensor that monitors the oxygen partial pressure of the gas. That is, the gas controlled to the target oxygen partial pressure can be purified by the oxygen pump, and the oxygen partial pressure of the purified gas can be inspected to stabilize the gas controlled to the target oxygen partial pressure. Can be supplied to the tank. In particular, by providing the electric control unit, the gas purification unit can be controlled with higher accuracy, and a high-quality purified gas can be purified.

  Further, by arranging the electric control unit on one side of any one of the boxes in which the circulation circuit is accommodated, the entire apparatus can be made compact. In addition, the operator can easily operate the electric control unit, and the workability is excellent. Furthermore, by arranging the pump that circulates the gas in the circulation circuit at the intermediate position in the vertical direction of the box, the piping on the pump outflow side and the piping on the pump inflow side can be arranged with a good balance in the vertical direction. Stable circulation is possible.

FIG. 1 shows an oxygen partial pressure control device according to the present invention. This oxygen partial pressure control device includes a plurality (two in the illustrated example) of tanks (buffer tanks) 20A and 20B and 0.2 to ^10-30 atm. A recirculation circuit 19 having a gas purifying unit 21 for purifying a gas whose oxygen partial pressure is controlled within a range, and the tanks 20A and 20B are filled with the purifying gas purified by the gas purifying unit 21. To another apparatus (for example, a sample preparation chamber).

  The gas purification unit 21 includes an electrochemical oxygen pump 14 that can control the gas to a target oxygen partial pressure, an upstream oxygen sensor 15A that monitors the oxygen partial pressure of the gas before flowing into the oxygen pump 14, And a downstream oxygen sensor 15B that monitors the oxygen partial pressure of the gas controlled by the oxygen pump. Further, on the upstream side of the upstream oxygen sensor 15A, a pressure adjusting valve (REG) 22 for adjusting the pressure of the gas passing through the switching valve 12 and a gas flow rate passing through the pressure adjusting valve (REG) are set. A mass flow controller (MFC) 13 that controls the value is arranged.

  As the oxygen pump 14, a solid electrolyte cylindrical body having oxide ion conductivity in which electrodes made of platinum are formed on both the inside and outside surfaces, that is, a structure similar to the oxygen pump 4 shown in FIG. 9 is used. be able to. For this reason, the description of the configuration and principle of the oxygen pump 14 is omitted here.

  As for the oxygen sensors 15A and 15B, as in the case of the oxygen pump 14, a sensor in which electrodes made of platinum are formed on both the inner and outer surfaces of a solid electrolyte cylindrical body having oxide ion conductivity can be used. Then, the potential difference between the inner surface side electrode and the outer surface side electrode is measured, and the oxygen partial pressure can be obtained from the Nernst equation based on thermodynamics.

  Further, the oxygen partial pressure control device includes an oxygen partial pressure setting unit 16 for setting a desired oxygen partial pressure value, and monitor values obtained by the upstream oxygen sensor 15A and the downstream oxygen sensor 15B as oxygen partial pressure setting unit 16. The oxygen partial pressure control unit 17 such as a PID control system for controlling the oxygen partial pressure of the gas delivered from the oxygen pump 14 to a predetermined value as compared with the set value by the oxygen pump, and the oxygen partial pressure set value by the oxygen partial pressure setting unit 16 And an oxygen partial pressure display unit 18 for displaying monitor values obtained by the oxygen sensors 15A and 15B.

  The outlet side of the gas purification unit 21 and the pair of tanks 20A and 20B are connected via the first circulation path 25, and the inlet side of the gas purification unit 21 and the pair of tanks 20A and 20B are connected to the second circulation path 26. It is connected through.

  The first circulation path 25 includes a main body pipe 29 in which a flow rate adjusting valve 27 and a pump (for example, a diaphragm pump) 28 are interposed, and first and second branch pipes 30 a and 30 b branched from the main body pipe 29. Prepare. Note that switching valves 31 and 32 are interposed in the branch pipes 30a and 30b, respectively.

  The second circulation path 26 includes a main body pipe 34 in which a switching valve 33 is interposed, and first and second branch pipes 35 a and 35 b branched from the main body pipe 34. Note that switching valves 36 and 37 are interposed in the branch pipes 35a and 35b, respectively.

  The second circulation path 26 is connected to an outflow path 38 for supplying purified gas to another device (for example, a sample preparation chamber or the like). The outflow path 38 includes a downstream pipe 40 in which the MFC 39 is interposed, a connection pipe 41 a that connects the downstream pipe 40 and the first branch pipe 35 a of the second circulation path 26, and the downstream pipe 40 and the second circulation. And a connecting pipe 41b for connecting the second branch pipe 35b of the passage 26. Pressure regulating valves (REG) 42 and 43 and switching valves 44 and 45 are interposed in the connecting pipes 41a and 41b, respectively.

  In this apparatus, as shown in FIGS. 2 to 5, a circulation circuit 19 having tanks 20 </ b> A and 20 </ b> B and a gas purification unit 21 is accommodated in a box 50. That is, the box 50 includes a lower tank accommodating portion 51 that accommodates the tanks 20A and 20B, an upper rear gas purifying portion accommodating portion 52 that accommodates the gas purifying portion 21, and an upper rear pump accommodating portion that accommodates the pump 28. 53 and a front control unit accommodating portion 54 that accommodates the electric control unit 49.

  Therefore, the box 50 includes a partition plate 55 for separating the upper and lower sides, a partition plate 56 for separating the left and right sides, and a partition plate 57 for separating the front and rear sides. The tanks 20 </ b> A and 20 </ b> B are placed and fixed on the bottom wall 50 b of the box 50, a support base 60 is provided on the partition plate 55, and the pump 28 is placed and fixed on the support base 60.

  Further, the oxygen pump 14 and the oxygen sensors 15A and 15B of the gas purification unit 21 are fixed in the gas purification unit accommodating unit 52 via a fixing frame or the like (not shown). Further, the gas outlet 61 of the gas outflow passage 38 opens upward through the upper wall 50 a of the box 50. 5 to 7, for the sake of simplification, piping constituting the circulation circuit 19 such as connection piping between the tanks 20A and 20B and the gas purification unit 21 is omitted. Further, casters 65 and height adjusting legs 66 are attached to the four corners of the bottom wall 50 b of the box 50.

  As described above, in the circulation circuit 19, the tanks 20A and 20B are disposed at the lower position, the gas outlet 61 is disposed at the upper position, and the purified gas in the tanks 20A and 20B is transferred to the other apparatus. 61 will be supplied. In addition, the electric control unit 49 is disposed on one surface side (one front side in the illustrated example) of the box 50 in which the circulation circuit 19 is accommodated, and the pump 28 for circulating the gas in the circulation circuit is provided in the box. It is arranged at 50 intermediate positions in the vertical direction.

Next, the operation of the oxygen partial pressure control apparatus shown in FIG. 1 will be described. In this case, the tanks 20A shown in FIG. 5, the step of filling the raw material gas to 20B, each tank 20A shown in FIG. 6, the oxygen partial pressure of the material gas and 20B in the range of 0.2 to 10 ^-30 atm control FIG. 7 shows a step of purifying the purified gas from the first tank 20A shown in FIG. 7 into the sample preparation chamber and the like, and a step of purifying the source gas of the second tank 20B into a purified gas. The first tank 20A shown in FIG. 8 is filled with the source gas and the purified gas in the second tank 20B is blown out (supplied) to the sample preparation chamber or the like, and the gas in the first tank 20A shown in FIG. Purifying and supplying (supplying) the purified gas from the second tank 20B to the sample preparation chamber and the like, and blowing (supply) the purified gas from the first tank 20A shown in FIG. 10 to the sample preparation chamber and the like. With the second There is a process of filling the raw material gas into the tank 20B. 5 to 10, the illustration of the oxygen partial pressure control unit 17 and the like is omitted. 5 to 10, in each switching valve 12, 31, 32, 33, 36, 37, 44, 45, the white state is shown as an open state, and the black case is shown as a closed state. 19, in the gas outflow passage 38 and the gas inflow passage 24, a thick line indicates that gas is flowing.

  In the step shown in FIG. 5, the switching valves 31, 32 of the first circulation path 25 are opened, and the switching valves 33, 36, 37, 44, 45 of the second circulation path 26 are closed, and the pump 28 is driven. . As a result, the raw material gas (process gas) flows into the first circulation path 25 through the gas purification unit 21 through the switching valve 12 of the gas inflow path 24.

  Then, the raw material gas flows into the main body pipe 29 of the first circulation path 25, the flow rate is adjusted by the flow rate adjustment valve 27, and flows into the branch paths 30 a and 30 b of the first circulation path 25 via the pump 28. The tanks 20A and 20B flow into the tanks 20A and 20B, respectively. Since the switching valves 36, 37, 44, 45 of the second circulation path 26 are closed, the raw material gas that has flowed into the tanks 20 </ b> A, 20 </ b> B does not flow out to the second circulation path 26. That is, as shown by the arrow A, the untreated raw material gas flows through the gas inflow path 24, the gas purification unit 21, the first circulation path 25, and the tanks 20A and 20B, and is sequentially supplied to the tanks 20A and 20B. .

  As described above, when the tanks 20A and 20B are filled with the raw material gas, the switching valve 12 is closed from the state shown in FIG. 5 and the switching valve 33 of the second circulation path 26 is closed as shown in FIG. , 36, 37 are opened.

  As a result, a circulation circuit 19 including the tanks 20A and 20B, the second circulation path 26, the gas purification unit 21, and the first circulation path 25 is configured, and the inside of the circulation circuit 19 is driven by the pump 28. Gas circulates as shown by arrow B.

In this state, the gas flowing through the gas purification unit 21 is purified by the gas purification unit 21. That is, the oxygen partial pressure setting unit 16 sets a desired oxygen partial pressure, for example, 1 × 10 ⁻²¹ to 1 × 10 ⁻³⁰ atm. Then, a control signal for setting the oxygen partial pressure set by the oxygen partial pressure setting unit 16 is sent from the oxygen partial pressure control unit 17 to the oxygen pump 14. The current I of the oxygen pump 14 is controlled by the control signal, and the oxygen partial pressure in the gas supplied to the oxygen pump 14 through the REG 22 and the mass flow controller (MFC) 13 is set by the oxygen partial pressure setting unit 16. The oxygen partial pressure is controlled to about 1 × 10 ⁻²¹ to 1 × 10 ⁻³⁰ atm.

The gas flowing through the gas purifying unit 21 is monitored for its oxygen partial pressure by the upstream oxygen sensor 15A and the downstream oxygen sensor 15B. The monitored value is displayed on the oxygen partial pressure display unit 18 and the oxygen partial pressure. Input to the controller 17. In this way, the monitor values monitored by the oxygen sensors 15A and 15B are input to the oxygen partial pressure control unit 17 and compared with the set values set by the oxygen partial pressure setting unit 16, and the oxygen partial pressure is then detected by the oxygen pump 14. It is checked whether or not the gas whose gas pressure is controlled is controlled to the oxygen partial pressure set by the oxygen partial pressure setting unit 16. If the oxygen partial pressure monitored by the oxygen sensor 15B does not coincide with the oxygen partial pressure set by the oxygen partial pressure setting unit 16, a control signal is output from the oxygen partial pressure control unit 17 to the oxygen pump 14. Then, by adjusting the current I flowing through the oxygen pump 14, a gas (purified gas) controlled to have an oxygen partial pressure of about 1 × 10 ⁻²¹ to 1 × 10 ⁻³⁰ atm is supplied to the first circulation path 25. The

Therefore, the purified gas is supplied to the tanks 20A and 20B, and the amount of gas (mixed gas of the purified gas and the untreated raw material gas) flowing into the tanks 20A and 20B from the tanks 20A and 20B is second circulated. The gas flows out to the passage 26, and this gas flows through the gas purification unit 21 again. As a result, a gas (purified gas) controlled to have an oxygen partial pressure of about 1 × 10 ⁻²¹ to 1 × 10 ⁻³⁰ atmospheres is also supplied to the first circulation path 25. That is, when the gas flows through the circulation circuit 19, the gas is purified to a gas controlled to have an oxygen partial pressure of about 1 × 10 ⁻²¹ to 1 × 10 ⁻³⁰ atm in the tanks 20A and 20B.

  Thus, if the gas of tank 20A, 20B is refine | purified, the refined gas of each tank 20A, 20B will be sent to a sample preparation room. In this case, as shown in FIG. 7, the purified gas in the first tank 20A is first blown into the sample preparation chamber. That is, as shown in FIG. 7 from the state shown in FIG. 6, the switching valve 31 of the first circulation path 25 is closed, the switching valve 36 of the second circulation path 26 is closed, and the switching valve 44 is opened. And

  As a result, the purified gas in the positive pressure first tank 20 </ b> A flows out to the first connection pipe 41 a of the outflow path 38. Then, the purified gas is blown into the sample preparation chamber via a mass flow controller (MFC) 39 that controls the flow rate of the purified gas that has passed through the pressure regulating valve (REG) 42 to a set value. That is, the purified gas in the first tank 20A flows through the outflow path 38 as shown by the arrow C1 and is supplied to the sample preparation chamber.

  Further, the gas in the tank 20B is indicated by the arrow B1 in the circulation circuit 19B composed of the second tank 20B, the branch pipe 35b, the main body pipe 34, the gas purification unit 21, the main body pipe 29, and the branch pipe 30b. In this way, gas purification is continued.

  When the supply of the purified gas from the first tank 20A to the sample preparation chamber is completed, the purified gas from the positive second tank 20B is blown into the sample preparation chamber, as shown in FIG. That is, from the state shown in FIG. 7, as shown in FIG. 8, the switching valve 31 of the first circulation path 25 is opened and the switching valve 32 is closed. Further, the switching valves 33, 37, 44 of the second circulation path 26 are closed, and the switching valve 45 is opened.

  As a result, the purified gas in the second tank 20B flows out to the first connection pipe 41b of the outflow path 38. And it blows off to the sample preparation chamber via the mass flow controller (MFC) 39 which controls the flow rate of the gas which passed through the pressure regulation valve (REG) 43 to a set value. That is, the purified gas in the second tank 20B flows through the outflow path 38 as indicated by arrow C2 and is supplied to the sample preparation chamber.

  Further, in the state shown in FIG. 8, the raw material gas is supplied to the gas inflow passage 24. That is, as shown by the arrow A1, the source gas flows into the gas inflow path 24, the gas purifying unit 21, the main body pipe 29 and the branch pipe 30a of the first circulation path 25, and the first tank 20A. The first tank 20A is filled with the source gas.

  Next, as shown in FIG. 9, the raw material gas filled in the first tank 20A is purified. That is, as shown in FIG. 9 from the state shown in FIG. 8, the switching valves 36 and 33 of the second circulation path 25 are opened. Thereby, the circulation circuit 19A constituted by the first tank 20A, the branch pipe 35a and the main body pipe 34 of the first circulation path 26, the gas purification unit 21, the main body pipe 29 and the branch pipe 30a of the first circulation path 25, Gas circulates as shown by arrow B2.

  By this circulation, the gas in the first tank 20A is purified again. During gas purification, the purified gas in the second tank 20B flows through the outflow path 38 as indicated by arrow C2 and is supplied to the sample preparation chamber.

  Further, when the supply of the purified gas from the second tank 20B to the sample preparation chamber is completed, the source gas is filled again in the second tank 20B as shown in FIG. That is, as shown in FIG. 10 from the state shown in FIG. 9, the switching valve 31 of the first circulation path 25 is closed, the switching valve 32 is opened, and the switching valve 33 of the second circulation path 26 is further opened. , 36 and 45 are closed, and the switching valve 44 is opened.

  As a result, the source gas flows through the gas inflow path 24, the gas purification section 21, the main body pipe 29 of the first circulation path 25, the branch pipe 30b, and the second tank 20B as indicated by the arrow A2, and the second tank 20B. The second tank 20B is filled with the source gas.

  Further, while the source gas is filled in the second tank 20B, the purified gas flows out from the first tank 20A to the connecting pipe 41a of the gas outflow path 38. That is, the purified gas in the first tank 20A flows through the outflow passage 38 as indicated by the arrow C1 and is supplied to the sample preparation chamber. Thereafter, returning to the steps shown in FIG. 7, the above steps are repeated until the operation of the apparatus stops.

In this way, the purified gas whose oxygen partial pressure is continuously controlled to 2 × 10 ⁻¹ to 1 × 10 ⁻³⁰ atm is supplied to the sample preparation chamber.

  In the present invention, the purified gas purified by the gas purification unit 21 can be stored in the tank 20, and the purified gas can be stably supplied to other apparatuses. In addition, since the purified gas is purified by the gas circulating in the circulation circuit 19, it is possible to purify the purified gas in a clean state and supply high-quality purified gas to other devices. That is, in the case where the purified gas supplied to other apparatuses is returned and sequentially supplied to the gas purification unit 21, it is difficult to maintain a clean state and there is a possibility that quality may be deteriorated. In addition, since the purified gas can be stored in the plurality of tanks 20, the ability to supply the purified gas to other apparatuses can be improved.

  Further, since the purified gas in the tank 20 disposed at the lower position is supplied from the gas outlet 61 at the upper position to another apparatus, even if impurities such as contamination are mixed into the purified gas, the tank 20 and the gas flow It stays between the outlet 61 and in the tank 20 to prevent such outflow of impurities from the gas outlet 61. The purified gas in a stable and clean state can be supplied to another apparatus, and the other apparatus can stably perform high-precision processing using this purified gas.

  The gas purification unit 21 includes an electrochemical oxygen pump 14 that can control a gas to a target oxygen partial pressure, and an oxygen sensor 15 that monitors the oxygen partial pressure of the gas. That is, the gas controlled to the target oxygen partial pressure can be purified by the oxygen pump 14, and the oxygen partial pressure of the purified gas can be inspected to stabilize the gas controlled to the target oxygen partial pressure. Then, it can be supplied to the tank 20. In particular, by providing the electric control unit 49, the gas purification unit can be controlled with higher accuracy, and a high-quality purified gas can be purified. In addition, by arranging the oxygen sensors 15A and 15B on the upstream side and the downstream side of the oxygen pump 14, the gas to be purified by the oxygen pump 14 can be easily adjusted, and the gas controlled to a more accurate oxygen partial pressure can be obtained. Can be purified.

  Further, by arranging the electric control unit 49 on either side of the box in which the circulation circuit 19 is accommodated, the entire apparatus can be made compact. In addition, the operator can easily operate the electric control unit 49, and the workability is excellent. Further, by arranging the pump 28 for circulating the gas in the circulation circuit 19 at the intermediate position in the vertical direction of the box 50, the pump outflow side piping and the pump inflow side piping can be arranged in a well-balanced manner. , Stable circulation of gas becomes possible.

  The switching valves 31, 32, etc. can constitute the first switching means 51 for switching the supply of the refined gas purified by the gas purification section 21 to the respective tanks and the supply stop, and the switching valves 36, 37, 44, 45 etc. can constitute the 2nd switching means 52 which switches supply of the refined gas of each tank 20A, 20B to other devices, and supply stop.

  For this reason, the first switching means 51 and the second switching means 52 (in this case, constituted by the switching valves 31, 32, 36, 44, etc.) are switched so that another device (sample preparation chamber) is connected from the first tank 20A. And the like, and by switching the first switching means 51 and the second switching means 52 (in this case, composed of the switching valves 31, 32, 33, 37, 45, etc.), In the gas supply permissible state from one tank 20A, the raw gas is filled in the second tank 20B after the supply of the purified gas to the other apparatus is completed, and the purified gas purified by the gas purification unit 21 is supplied. Can be.

  That is, in the present invention, by switching between the first switching means 51 and the second switching means 52, the gas circulated in the apparatus can be continuously and purified gas can be blown out to other apparatuses. In the apparatus, processing using purified gas can be performed stably. In addition, the 1st switching means 51 and the 2nd switching means 52 can each be comprised by the combination of the switching valve arbitrarily selected from the switching valves 31, 32, 33, 36, 37, 44, 45, etc.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and various modifications are possible. For example, even if there is one tank, there are three or more. Also good. In the case of having three or more tanks, purified gas can be supplied simultaneously from two or more tanks to the sample preparation room, etc., or the purified gas can be stored in two or more tanks. Various operations can be selected according to the amount used.

  In addition, a plurality of gas purification units 21 may be provided. As long as a plurality of gas purification units 21 are provided, the gas purification capacity can be increased, and the purified gas can be stably supplied to other apparatuses. For this reason, it can fully respond also to the apparatus which requires a lot of refined gas, and the use which supplies gas is not restrict | limited.

  In the above embodiment, the oxygen sensors 15A and 15B are arranged on the upstream side and the downstream side of the oxygen pump 14, but the upstream oxygen sensor 15A may be omitted. That is, it is sufficient that the oxygen partial pressure of the gas purified by the oxygen pump 14 is inspected and the purified gas can be controlled to a desired partial pressure. Therefore, the downstream partial oxygen sensor 15B can be sufficiently controlled to a desired partial pressure. Because.

  Further, when it is not necessary to consider the generation of impurities in the sample preparation chamber, or when the generated impurities can be removed, the used purified gas exhausted from the sample preparation chamber is returned to the gas purification section 21. May be reused. If all of the inert gas supplied to the sample preparation chamber is covered with new supply gas, the load on the oxygen pump 14 increases, which not only increases the size and cost of the equipment, but also increases the installation space. The cost for controlling the oxygen partial pressure to a predetermined value also increases.

  However, the used purified gas discharged from the sample preparation chamber is naturally higher in oxygen partial pressure than the purified gas supplied to the sample preparation chamber by controlling the oxygen partial pressure by the oxygen pump 14. Compared to the new supply gas supplied from the valve 2 for use, the oxygen partial pressure is much lower. Therefore, if a return pipe or the like is provided and the used purified gas exhausted from the sample preparation chamber is returned to the gas purification unit 21 and reused, the supply gas is compared to a case where only a new source gas is supplied. As well as reducing the amount of oxygen used, the load on the oxygen pump 14 can be reduced to achieve downsizing and cost reduction, the installation space can be reduced, and the cost for controlling the oxygen partial pressure to a predetermined value is also reduced. it can.

It is a simplified diagram of an oxygen partial pressure control device showing an embodiment of the present invention. It is a simplified sectional view of the oxygen partial pressure control device. It is a simplified side view of the oxygen partial pressure control device. It is a simplified top view of the oxygen partial pressure control device. It is a simplified diagram of the oxygen partial pressure control device showing a raw material gas filling process into a tank. It is a simplified diagram of the oxygen partial pressure control device showing a gas purification process. FIG. 3 is a simplified diagram of the oxygen partial pressure control device showing a purified gas supply process from a first tank to a sample preparation chamber and a purified process of a second tank. FIG. 3 is a simplified diagram of the oxygen partial pressure control device showing a purified gas supply process from a second tank to a sample preparation chamber and a gas filling process to the first tank. FIG. 3 is a simplified diagram of the oxygen partial pressure control device showing a purified gas supply process from the second tank to the sample preparation quality and a gas purification process of the first tank. FIG. 4 is a simplified diagram of the oxygen partial pressure control device showing a purified gas supply process from a first tank to a sample preparation chamber and a source gas filling process to a second tank. It is a simplified diagram of a conventional oxygen partial pressure control device. It is explanatory drawing of the principle of an oxygen pump.

Explanation of symbols

14 Oxygen pump 15 Oxygen sensor 16 Oxygen partial pressure setting unit 17 Oxygen partial pressure control unit 19 Circulation circuit 20 Tank 21 Gas purification unit 24 Gas inflow path 28 Pump 49 Electric control unit 50 Box 61 Gas outlet

Claims (3)

A gas purification unit for purifying a gas whose oxygen partial pressure is controlled in the range of 0.2 to ^10-30 atm, and a circulation circuit having a tank, and circulating the source gas filled in the tank through the circulation circuit, An oxygen partial pressure control device for storing purified gas to be purified in a gas purification unit in a tank,
In the circulation circuit, the tank is disposed at a lower position, a gas outlet is disposed at an upper position, and purified gas in the tank is supplied to another device via the gas outlet. Oxygen partial pressure control device.   An oxygen partial pressure setting unit for setting a desired oxygen partial pressure value, and a monitored value by the oxygen sensor are compared with a set value by the oxygen partial pressure setting unit to control the oxygen partial pressure of the gas delivered from the oxygen pump to a predetermined value. 2. An oxygen partial pressure control apparatus according to claim 1, further comprising an electric control unit having an oxygen partial pressure control unit, wherein the electric control unit is arranged on one side of a box in which the circulation circuit is accommodated. .   3. The oxygen partial pressure control apparatus according to claim 2, wherein a pump for circulating the gas in the circulation circuit is arranged at an intermediate position in the vertical direction of the box.